Denver Health and Hospital Authority, Department of Obstetrics and Gynecology, Denver, CO; Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver, Denver, CO.
University of Colorado School of Medicine, Department of Obstetrics and Gynecology, Aurora, CO.
Am J Obstet Gynecol MFM. 2019 Aug;1(3):100032. doi: 10.1016/j.ajogmf.2019.100032. Epub 2019 Aug 5.
Labor dystocia has been identified as a contributor to the rising cesarean delivery rate in the United States. Allowing more time for vaginal delivery, while being cognizant of maternal and neonatal outcomes, has been identified as a possible strategy to lower cesarean delivery rates.
This study aimed to characterize the relationship between the duration of active phase and second-stage labor and maternal and neonatal morbidity.
We present a secondary analysis of the Consortium on Safe Labor project. From labors of 66,940 nonanomalous nulliparous term singleton vertex gestations, we excluded labors for which active phase (≥6 cm dilation) or second stage durations could not be calculated and from sites that did not report determinants of morbidity. For each duration of active phase or second stage labor (grouped in 1-hour increments), the adjusted maternal and neonatal composite morbidity was estimated by and compared with the morbidity associated with a duration <1 hour total and a duration of 1 hour shorter.
After exclusions, 48,144 deliveries remained. In adjusted models, compared with labor durations <1 hour total, maternal composite morbidity was significantly higher across active phase and second stage durations (both P<.001); neonatal composite morbidity was higher across the second stage (P<.001), but not active phase (P=.07) duration. These relationships appear linear with no apparent inflection point, and morbidity increases more rapidly. When compared with labor durations 1 hour shorter, significant differences persisted in maternal and neonatal composite morbidity in second stage labor only through 4 and 3 hours, respectively.
Maternal and neonatal composite morbidity is greater with longer durations of active and second stage labor; however, no clear cutoff point was determined to suggest truncation of either stage of labor for reasons of morbidity. In addition, incrementally higher morbidities that were noted vs duration <1 hour total were obscured when comparison was made with labors 1 hour shorter, which suggests that focusing on short differences in duration of labor may mask important underlying trends.
劳动分娩困难已被确定为导致美国剖宫产率上升的原因之一。人们已经认识到，为阴道分娩留出更多时间，同时关注母婴结局，可以作为降低剖宫产率的一种可能策略。
本研究旨在描述活跃期和第二产程时长与母婴发病的关系。
我们对安全分娩联盟项目进行了二次分析。在 66940 例非畸形初产妇足月单胎头位妊娠中，我们排除了活跃期（≥6cm 扩张）或第二产程时长无法计算的分娩，以及未报告发病相关因素的分娩地点。对于每个活跃期或第二产程时长（每 1 小时分组），通过与总时长<1 小时和短 1 小时的分娩相关的发病情况比较，估计调整后的母婴复合发病情况。
排除后，有 48144 例分娩仍保留。在调整后的模型中，与总时长<1 小时的分娩相比，活跃期和第二产程时长的产妇复合发病情况显著更高（均 P<.001）；新生儿复合发病情况在第二产程更高（P<.001），但在活跃期（P=.07）则不然。这些关系呈线性，没有明显的拐点，发病率增加得更快。与第二产程时长短 1 小时相比，仅在 4 小时和 3 小时时，母婴复合发病情况仍存在显著差异。
活跃期和第二产程时长与产妇和新生儿复合发病情况增加有关；然而，没有确定明确的截断点来建议因发病而缩短分娩的任何阶段。此外，与总时长<1 小时的分娩相比，当与短 1 小时的分娩相比时，递增更高的发病情况被掩盖，这表明关注分娩时长的短差异可能掩盖了重要的潜在趋势。
